What is Bash?

Bash is the GNU Project's Bourne Again SHell, a complete implementation of the IEEE POSIX and Open Group shell specification with interactive command line editing, job control on architectures that support it, csh-like features such as history substitution and brace expansion, and a slew of other features.

How to use this image

The primary use cases this image is targeting are testing new features of more recent Bash versions before your primary distribution updates packages and testing shell scripts against different Bash versions to ensure compatibility. There are likely other interesting use cases as well, but those are the primary two the image was initially created to solve!

Notes

There are a few main things that are important to note regarding this image:

Bash itself is installed at /usr/local/bin/bash, not /bin/bash, so the recommended shebang is #!/usr/bin/env bash, not #!/bin/bash (or explicitly running your script via bash /.../script.sh instead of letting the shebang invoke Bash automatically). The image does not include /bin/bash, but if it is installed via the package manager included in the image, that package will install to /bin/bash and might cause confusion (although /usr/local/bin is ahead of /bin in $PATH, so as long as plain bash or /usr/bin/env are used consistently, the image-provided Bash will be preferred).

Bash is the only thing included, so if your scripts rely on external tools (such as jq, for example), those will need to be added manually (via apk add --no-cache jq, for example).

License

As with all Docker images, these likely also contain other software which may be under other licenses (such as Bash, etc from the base distribution, along with any direct or indirect dependencies of the primary software being contained).